CONSOLIDATED STATEMENT OF CHANGES IN PARTNERS' EQUITY (USD $) In Millions, unless otherwise specified		Common Units (Limited Partners) Former parent, TransCanada subsidiaries GTN and Bison	Common Units (Limited Partners) GTN and Bison	Common Units (Limited Partners) Bison	Common Units (Limited Partners) Equity Issuance, May 2013	Common Units (Limited Partners) ATM Equity Issuance Program	Common Units (Limited Partners)	General Partner Former parent, TransCanada subsidiaries GTN and Bison	General Partner GTN and Bison	General Partner Equity Issuance, May 2013	General Partner ATM Equity Issuance Program	General Partner	Accumulated Other Comprehensive Loss		Non-controlling interests Bison	Non-controlling interests Bison	Non-controlling interests	Equity of former parent Former parent, TransCanada subsidiaries GTN and Bison	Equity of former parent GTN and Bison	Equity of former parent Bison	GTN and Bison	Bison	GTN and Bison	Bison	Equity Issuance, May 2013	ATM Equity Issuance Program	Total
Partners' Equity at beginning of year at Dec. 31, 2011	[1]						$ 1,307					$ 27	$ (1)	[2]			$ 465		$ 698								$ 2,496
Partners' Equity at beginning of year (in units) at Dec. 31, 2011							53.5
Increase (Decrease) in Partners' Equity
Net income	[1]						188					4					37										229
Net income attributed to GTN and Bison's former parent	[1]	(54)						(1)										55
Distribution paid related to equity of former parent																			(81)		(81)
Effect of conversion to an LLC by GTN and other (Note 6)	[1]																(1)		1
Distributions paid	[1]						(166)					(3)					(53)										(222)
Partners' Equity at end of year at Dec. 31, 2012	[1]						1,275					27	(1)	[2]			448		673								2,422
Partners' Equity at End of Year (in units) at Dec. 31, 2012							53.5
Increase (Decrease) in Partners' Equity
Net income	[1]						152					3					36										191
Net income attributed to GTN and Bison's former parent	[1]	(26)																26
Distribution paid related to equity of former parent																			(37)		(37)
Equity issuance, net (Note 9)					373					8															381
Equity issuance (Note 9) (in units)					8.8
Acquisition of the remaining 30 percent interest, 2014; Excess purchase price paid over net acquired assets, 2013 (Note 6)			(268)						(6)														(274)
Distributions paid							(184)					(4)					(52)										(240)
Former parent carrying amount of acquired entities																			(672)		(672)
Adjustment to the 2011 Acquisition							1																				1
Other							(1)																				(1)
Equity contributions from former parent															8					10		18
Partners' Equity at end of year at Dec. 31, 2013							1,322					28	(1)	[2]			440										1,789
Partners' Equity at End of Year (in units) at Dec. 31, 2013							62.3
Increase (Decrease) in Partners' Equity
Net income							168					4					32										204
Other comprehensive loss													(1)	[2]													(1)
Equity issuance, net (Note 9)						71					2															73
Equity issuance (Note 9) (in units)						1.3
Acquisition of the remaining 30 percent interest, 2014; Excess purchase price paid over net acquired assets, 2013 (Note 6)				(29)												(188)								(217)
Distributions paid							(207)					(5)					(50)										(262)
Partners' Equity at end of year at Dec. 31, 2014							$ 1,325					$ 29	$ (2)	[2]			$ 234										$ 1,586
Partners' Equity at End of Year (in units) at Dec. 31, 2014							63.6

[1] Recast as discussed in Note 2 and Note 6.

[2] Losses related to cash flow hedges reported in Accumulated Other Comprehensive Loss and expected to be reclassified to net income in the next 12 months are estimated to be less than $1 million. These estimates assume constant interest rates over time; however, the amounts reclassified will vary based on actual value of interest rates at the date of settlement.